Plugged tip delivery tube for marker placement

ABSTRACT

An intracorporeal marker delivery device includes a delivery tube which has a distal tip, a discharge orifice and an inner bore extending to the discharge orifice. A plug is releasably secured within the inner bore. The plug may itself serve as a marker, and may be the sole marker. Markers may be positioned proximal to the plug, and may be detectable by ultrasound, X-ray, magnetic resonance imaging, and other imaging devices, and may include bioactive elements.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 12/592,020,filed Nov. 18, 2009, now U.S. Pat. No. 8,177,792, which is acontinuation of application Ser. No. 10/174,401, filed Jun. 17, 2002,now U.S. Pat. No. 7,651,505, each of which is incorporated by referenceherein in its entirety and from which priority is claimed.

FIELD OF THE INVENTION

The invention is directed generally to devices and methods fordelivering markers to a desired location within a patient's body. Inparticular, the invention is directed to devices, assemblies, andmethods configured to retain a biological marker within a deliverydevice before delivery of the marker to a desired intracorporeallocation.

BACKGROUND OF THE INVENTION

In diagnosing and treating certain medical conditions, it is oftendesirable to mark a suspicious body site for the subsequent taking of abiopsy, delivery of medicine, radiation, or other treatment, to mark alocation from which a biopsy was taken, or at which some other procedurewas performed. As is known, obtaining a tissue sample by biopsy and thesubsequent examination are typically employed in the diagnosis ofcancers and other malignant tumors, or to confirm that a suspectedlesion or tumor is not malignant. The information obtained from thesediagnostic tests and/or examinations is frequently used to devise atherapeutic plan for the appropriate surgical procedure or other courseof treatment.

In many instances, the suspicious tissue to be sampled is located in asubcutaneous site, such as inside a human breast. To minimize surgicalintrusion into patient's body, it is often desirable to insert a smallinstrument, such as a biopsy needle, into the body for extracting thebiopsy specimen while imaging the procedure using fluoroscopy,ultrasonic imaging, x-rays, magnetic resonance imaging (MRI) or anyother suitable form of imaging technique. Examination of tissue samplestaken by biopsy is of particular significance in the diagnosis andtreatment of breast cancer. In the ensuing discussion, the biopsy andtreatment site described will generally be the human breast, althoughthe invention is suitable for marking biopsy sites in other parts of thehuman and other mammalian body as well.

Periodic physical examination of the breasts and mammography areimportant for early detection of potentially cancerous lesions. Inmammography, the breast is compressed between two plates whilespecialized x-ray images are taken. If an abnormal mass in the breast isfound by physical examination or mammography, ultrasound may be used todetermine whether the mass is a solid tumor or a fluid-filled cyst.Solid masses are usually subjected to some type of tissue biopsy todetermine if the mass is cancerous.

If a solid mass or lesion is large enough to be palpable, a tissuespecimen can be removed from the mass by a variety of techniques,including but not limited to open surgical biopsy, a technique known asFine Needle Aspiration Biopsy (FNAB) and instruments characterized as“vacuum assisted large core biopsy devices”.

If a solid mass of the breast is small and non-palpable (e.g., the typetypically discovered through mammography), a biopsy procedure known asstereotactic needle biopsy may be used. In performing a stereotacticneedle biopsy of a breast, the patient lies on a special biopsy tablewith her breast compressed between the plates of a mammography apparatusand two separate x-rays or digital video views are taken from twodifferent points of view. A computer calculates the exact position ofthe lesion as well as depth of the lesion within the breast. Thereafter,a mechanical stereotactic apparatus is programmed with the coordinatesand depth information calculated by the computer, and such apparatus isused to precisely advance the biopsy needle into the small lesion.Depending on the type of biopsy needle(s) used, this stereotactictechnique may be used to obtain cytologic specimens, e.g., obtainedthrough FNAB or it may be used to obtain histologic specimens e.g.,obtained through coring needle biopsy. Usually at least five separatebiopsy specimens are obtained from locations around the small lesion aswell as one from the center of the lesion.

The available treatment options for cancerous lesions of the breastinclude various degrees of mastectomy or lumpectomy and radiationtherapy, as well as chemotherapy and combinations of these treatments.However, radiographically visible tissue features, originally observedin a mammogram, may be removed, altered or obscured by the biopsyprocedure, and may heal or otherwise become altered following thebiopsy. In order for the surgeon or radiation oncologist to directsurgical or radiation treatment to the precise location of the breastlesion several days or weeks after the biopsy procedure was performed,it is desirable that a biopsy site marker be placed in or on thepatient's body to serve as a landmark for subsequent location of thelesion site. A biopsy site marker may be a permanent marker (e.g., ametal marker visible under X-ray examination), or a temporary marker(e.g., a bioresorbable marker detectable with ultrasound). While currentradiographic type markers may persist at the biopsy site, an additionalmammography generally must be performed at the time of follow uptreatment or surgery in order to locate the site of the previous surgeryor biopsy. In addition, once the site of the previous procedure islocated using mammography, the site must usually be marked with alocation wire which has a hook on the end which is advanced into site ofthe previous procedure. The hook is meant to fix the tip of the locationwire with respect to the site of the previous procedure so that thepatient can then be removed from the confinement of the mammographyapparatus and the follow-up procedure performed. However, as the patientis removed from the mammography apparatus, or otherwise transported theposition of the location wire can change or shift in relation to thesite of the previous procedure. This, in turn, can result in follow-uptreatments being misdirected to an undesired portion of the patient'stissue.

As an alternative or adjunct to radiographic imaging, ultrasonic imagingand visualization techniques (herein abbreviated as “USI”) can be usedto image the tissue of interest at the site of interest during asurgical or biopsy procedure or follow-up procedure. USI is capable ofproviding precise location and imaging of suspicious tissue, surroundingtissue and biopsy instruments within the patient's body during aprocedure. Such imaging facilitates accurate and controllable removal orsampling of the suspicious tissue so as to minimize trauma tosurrounding healthy tissue.

For example, during a breast biopsy procedure, the biopsy device isoften imaged with USI while the device is being inserted into thepatient's breast and activated to remove a sample of suspicious breasttissue. As USI is often used to image tissue during follow-up treatment,it may be desirable to have a marker, similar to the radiographicmarkers discussed above, which can be placed in a patient's body at thesite of a surgical procedure and which are visible using USI. Such amarker enables a follow-up procedure to be performed without the needfor traditional radiographic mammography imaging which, as discussedabove, can be subject to inaccuracies as a result of shifting of thelocation wire as well as being tedious and uncomfortable for thepatient.

Placement of a marker or multiple markers at a location within apatient's body requires delivery devices capable of holding markerswithin the device until the device is properly situated within a breastor other body location. Accordingly, devices and methods for retainingmarkers within a marker delivery device while allowing their expulsionfrom the devices at desired intracorporeal locations are desired.

SUMMARY OF THE INVENTION

The invention provides devices and systems for delivery of markers to asite within a patient's body. Delivery systems embodying features of theinvention include a marker delivery tube with a removable plug. Plugsembodying features of the invention are held within an orifice at thetip of the delivery tube, retaining markers within the delivery tube,until it is desired that the markers be ejected. The plug may then beejected or removed from the orifice, allowing the delivery of themarkers to a desired site within a patient's body. Plugs and deliverytubes embodying features of the invention may have retaining features,such as recesses or protuberances, configured to releasably retain aplug within a delivery tube until ejection of the plug from the deliverytube is desired. The retaining features are typically complementarypairs, such as a plug protuberance configured to fit into a recess inthe delivery tube.

Assemblies embodying features of the invention include marker deliverydevices having a delivery tube with an orifice at its distal tip, aninner bore leading to an orifice, and at least one marker (preferablymore than one) within the bore of the delivery tube. A plug is disposedat least in part within the bore and orifice to prevent markers fromprematurely passing through the orifice and to prevent tissue fromentering the bore when the delivery tube is advanced through tissue. Theplug may itself serve as a marker, and may be the sole marker, althoughtypically the delivery tube contains a plug and at least one othermarker. The plug is releasably secured within or adjacent to the orificein order to retain a marker within the delivery tube bore proximatethereto but to allow passage of the marker out of the orifice when theplug is ejected from the orifice. The plug may partially or completelyocclude the orifice, and is configured to retain the marker within thedelivery tube before the marker is to be placed at a desired locationwithin a patient's body, and to allow the marker to pass out of theorifice when delivery of the marker is desired. A movable plunger may beslidably disposed within the tube from an initial position accommodatingthe marker or markers and the plug within the tube, to a deliveryposition to push a marker against the plug to push the plug out of theorifice and to then eject one or more markers through the orifice.

The plug is preferably configured to be releasably retained within thedelivery tube, and may be aligned in a preferred orientation within thedelivery tube, to properly orient an inclined face within the orifice. Aplug may be configured to fit tightly within a part of the bore of adelivery device so as to be retained by pressure; may have a portionconfigured to contact a slot, hole, notch, ridge, tab, lip, or otherfeature of a delivery tube; may be configured to be retained by a tab;may include an internal retention element, such as a coil, a spring, aclip, a loop, an arch, or a resilient core, that is configured to pressan outer portion of a plug against a delivery tube wall or to contact aretaining feature such as a tab, slot, notch or hole; may be pressedagainst at least part of the bore of a delivery tube by an externalretention element such as a pin, wedge, clip, spring, coil or otherelement applied to a plug; or by otherwise engaging a portion of adelivery tube effective to be releasably retained within a deliverytube.

The plug is preferably biocompatible, and may itself be a marker that isdetectable within a patient's body visually, tactilely, by imaging(including ultrasound, radiographic, magnetic resonance, or other formof imaging), or is otherwise detectable. A plug may be a bio-resorbabletemporary marker made up of bio-resorbable materials, or may be apermanent marker including non-bio-resorbable materials as well. A plugmay also include bio-active materials (e.g., hemostatic materials,anesthetic materials, absorbent materials, antibiotic materials,antifungal materials, antiviral materials, chemotherapeutic materials,radioactive materials, and other pharmaceutical materials) as well asbiologically inert materials.

Systems and devices embodying features of the invention may havemarkings or indicators to aid in placement of the delivery tube in adesired location. In addition, methods of using systems and devicesembodying features of the invention include guiding the insertion of thedelivery tube with the aid of an imaging device, such as an ultrasoundimaging device, an x-ray imaging device, and a magnetic resonanceimaging device, which may be used to image the plug, a marker retainedwithin the delivery device, a portion of the delivery device, orcombinations of these.

The invention provides the advantages of securely retaining markerswithin a marker delivery device, improving accuracy and avoiding errorsin of placement of markers at desired locations within a patient's body,preventing ingress of tissue into the distal tip of the device when itis advanced through tissue, and guiding the device by use of an imagingdevice. These and other advantages of the invention will become moreapparent from the following description when taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a partly cut-away perspective view of a marker deliveryassembly embodying features of the invention showing several markerswithin a marker delivery device and a plug embodying features of theinvention occluding the tip of the delivery device.

FIG. 1B is a transverse cross-sectional view of the marker deliveryassembly of FIG. 1A taken at line 1B-1B.

FIG. 1C is a transverse cross-sectional view of the marker deliveryassembly of FIG. 1A taken at line 1C-1C.

FIG. 1D is a transverse cross-sectional view of the marker deliveryassembly of FIG. 1A taken at line 1D-1D.

FIGS. 2A-2C and 2E-2H are longitudinal cross-sectional views of adelivery tube distal portion embodying features of the inventionconfigured to retain a plug, containing markers and a plug embodyingfeatures of the invention.

FIG. 2D is a transverse cross-sectional view of the delivery tube distalportion and plug shown in FIG. 2C.

FIG. 3A is a longitudinal cross-sectional view of a compressible plugembodying features of the invention disposed outside a distal portion ofa delivery tube.

FIG. 3B is a longitudinal cross-sectional view of the compressible plugof FIG. 3A embodying disposed within the distal portion of the deliverytube.

FIG. 3C is a longitudinal cross-sectional view of an alternativeembodiment of a compressible plug.

FIG. 3D is a longitudinal cross-section of a plug containing an internalretention element configured to press against the wall of a deliverytube.

FIG. 4A is a longitudinal cross-sectional view of a plug embodyingfeatures of the invention disposed outside a distal portion of adelivery tube.

FIG. 4B is a longitudinal cross-sectional view of an external retentionelement and of a plug embodying features of the invention disposedwithin a distal portion of a delivery tube.

FIG. 4C is a longitudinal cross-sectional view of the external retentionelement inserted into the plug of FIG. 4B embodying disposed within thedistal portion of the delivery tube.

FIG. 4D is a perspective view of a sharp tip of a delivery tube distalportion embodying features of the invention having slits forming a tabconfigured to retain and align a plug.

FIG. 4E is a longitudinal cross-section of a delivery tube distalportion embodying features of the invention having a tab configured toretain a plug, and containing a plug configured to be retained andaligned by a tab.

FIG. 4F is a longitudinal cross-section of a delivery tube distalportion embodying features of the invention having a tab configured toretain and align a plug, and containing a plug configured to be retainedby a tab.

FIGS. 5A-5H are alternating plan and elevation views of distal portionsof delivery tubes of marker delivery devices embodying features of theinvention configured to retain a plug by having holes or slots throughthe tube wall.

FIG. 6 is a partially cut away, perspective view of a human breasthaving a lesion from which a biopsy specimen has been removed, andshowing a guide cannula and a marker delivery assembly embodyingfeatures of the invention inserted into the breast, the assembly havingmarkers and a plug configured to retain the markers within a deliverytube of a delivery device.

DETAILED DESCRIPTION OF THE INVENTION

Marker delivery assemblies embodying features of the invention areillustrated in FIGS. 1A-1D. Such assemblies include marker deliverydevices, markers, and a plug occluding a distal portion of the deliverydevice. The assembly 10 shown in FIG. 1A includes a delivery device 12,delivery tube 14 with a bore 16, a distal portion 18, and a proximalportion 20 with a handle 22. Several markers 24, and a plug 26 are showndisposed within the bore 16. A plunger 28 with a plunger handle 30 and aplunger distal end 32 is movable within the tube bore 16, and isconfigured to push markers 24 and plug 26 out of orifice 34 at thedistal tip 36 of delivery tube 14 when the distal end 32 of plunger 28moves in a distal direction. Plunger handle 30 allows an operator toreadily manipulate plunger 28. A device 12 may include a plunger lockingmechanism to prevent inadvertent longitudinal movement of plunger 28;for example, a plunger 28 and a handle 22 may be configured so thatplunger 28 must be rotated some amount before it is able to be moved ina longitudinal direction (by, e.g., having a lateral tab protruding froma portion of the plunger 28 that prevents longitudinal plunger movementuntil the tab is moved to a channel configured to accept it).

Plug 26 may substantially fill orifice 34, as shown in FIG. 1A, or mayoccupy or block only a portion of orifice 34. A plug 26 preferably doesnot interfere with the sharp edge of orifice 34 or pointed tip 36 of adelivery tube 14. Where distal tip 36 of delivery tube 14 is sharp, asshown in FIG. 1A, the distal surface 38 of plug 26 is preferablyconfigured with an inclined surface to closely follow the conformationof distal tip 36 to provide more effective penetration.

Markers 24 are preferably configured to slide readily within tube bore16. Plug 26 is configured to be releasably secured within a portion oftube bore 16, such as a distal portion 18 or orifice 34, effective toprevent inadvertent exit or release of markers 24 from delivery tube 14.The engagement of plug 26 with delivery tube 14 is further configured tobe readily releasable when desired. For example, plug 26 is configuredto release its engagement with delivery tube 14 effective to allow exitof markers 24 upon distal movement of plunger 28. Markers 24 are madewith detectable, biocompatible materials, and may include a radiopaqueelement 40. Plug 26 may be made from the same or similar materials as amarker 24, and may also include a radiopaque element 40.

FIG. 1A shows a marker delivery device 12 having a delivery tube 14 witha distal tip 36 having a notch 42 configured to retain a plug 26. Anotch 42 is effective to retain a plug 26, particularly if a portion ofthe plug 26 is formed to engage with the notch 42, or is pressed orotherwise introduced into at least a portion of the notch 42. Thedelivery tube 14 also has markings 44 which aid in placement of thedevice in a desired location within a patient's body. The markings 44may serve as visual landmarks for guiding an operator in placing thedevice, and may also be radiopaque, ultrasound-reflective, or otherwiseconfigured to be detectable by imaging devices and imaging methods.

In FIG. 1B, the plug 26 is shown in place within tube bore 16 at thedistal portion 18 of delivery tube 14. In FIG. 1C, a marker 24 withradiopaque element 40 is shown within tube bore 16 of delivery tube 14.In FIG. 1D, a portion the plunger 28 is shown in place within tube bore16 of delivery tube 14.

FIGS. 2A-2H illustrate several alternative embodiments of a plug 26having features of the invention. The plugs 26 in FIGS. 2A-2C and 2E-2Hare shown in longitudinal cross-section within a distal portion 18 of adelivery tube 14 of a marker delivery device 12 embodying features ofthe invention. FIG. 2A illustrates a plug 26 configured to be retainedwithin a delivery tube 14 and to occlude an orifice 34. Plug 26 of FIG.2A is configured to provide a surface 38 following a configurationgenerally perpendicular to wall 46 conforming to the sharp tip 36,effective to aid the penetration of sharp tip 36 into a patient's tissueas well as to retain markers 24 within a delivery device 12. A plug 26embodying features of the invention may be retained within a deliverytube 14 effective to occlude an orifice 34 and to retain a marker 24 inany one or in more than one way. For example, a plug 26 may be retainedby friction, adhesion, tension, pressure, or other mechanisms; may beretained mechanically, as by a notch, hole, slot, tab, ridge, lip orother feature of a tube 14, of the plug 26 itself, or by any combinationof such elements; or by any other mechanism or method suitable toreleasably retain a plug while allowing its removal at a desired time.Some examples of such features and elements are illustrated in thefigures, although the devices, assemblies and elements embodyingfeatures of the invention are not limited to these examples. Anyfeature, element, or means of retaining a plug in a location effectiveto occlude an orifice 34 and to retain a marker 24 within a deliverytube 14, while allowing its removal at a desired time, is suitable forthe practice of the invention.

FIG. 2B illustrates a plug 26 having a protrusion 48 configured toengage a passage 50 through tube wall 46, aiding in the retention ofplug 26 within bore 16 of delivery tube 14. A passage 50 may be a hole,slot, notch, or other void through a tube wall 46. Alternatively, aprotrusion 48 of a plug 26 may engage a slot, notch, or crease along abore 16 that does not completely pass through the wall 46, yet stillprovides purchase for retaining a plug 26 within a delivery tube 14.

FIG. 2C illustrates a plug 26 embodying features of the invention havinga gap 52 allowing compression of plug 26 effective to allow insertion ofplug 26 into distal portion 18, where plug 26 occludes orifice 34.Resilience of plug 26 provides outward pressure following suchcompression, effective to provide lateral pressure against a wall 46 ofa delivery tube 14 and so to retain the plug 26 within distal portion 18of tube 14. The embodiment of a plug 26 illustrated in FIG. 2C also hasa lip portion 54 effective to limit the extent of insertion of plug 26into delivery tube 14. It will be understood that a lip portion 54 isoptional, and is not present in some plugs 26, including resilient plugs26 embodying features of the invention. Preferably, lip portion 54 isconfigured to leave a sufficient amount of distal tip 36 exposed so asto not substantially interfere with penetration of sharp tip 36 into thetissue of a patient. For example, a lip portion 54 preferably comprisesless than a full circumference a plug 26 having a round cross-section,and may comprise one or a few extensions 56 extending radially outwardlyform a plug body 58, as illustrated in FIG. 2D in a transversecross-sectional view of the plug 26 and tube 14 of FIG. 2C. A plug body58 may surround a gap 52, as in the plug 26 illustrated in FIGS. 2C and2D, or, in other embodiments, may not have a gap 52, as, e.g., in theplugs 26 illustrated in FIGS. 2A and 2B.

The plug 26 illustrated in FIG. 2E is an irregularly-shaped plug 26embodying features of the invention, configured to occlude an orifice 34and to retain markers 24 within a delivery tube 14 until the plug 26 isremoved or moved away from its blocking position. An irregularly-shapedplug 26 may be put into place, for example, by the application of aliquid, flexible or pliable material that sets or hardens afterplacement in or around an orifice 34. Alternatively, a material may beplaced in or around an orifice 34 and then treated with heat, solvent,hardener, or other treatment in order to fix the plug 26 in its finalform.

As illustrated by the embodiment of a plug 26 shown in FIG. 2F, anorifice 34 need not be completely occluded; partial occlusion of anorifice 34 by a plug 26 is sufficient to retain a marker 24 within adelivery tube 14. Such a plug 26 may be retained within the bore 16 of adelivery tube 14 by adhesion or other bonding to a tube wall 46, or by afeature of a tube 14 embodying features of the invention such as a tab,lip, hole, notch, slot, or other retaining element.

The embodiments of a plug 26 shown in FIGS. 2G and 2H include markermaterial effective to mark a location within a patient's body, and thusis configured to act as a marker 24 as well as a plug 26. For example, aplug 26 as illustrated in FIGS. 2G and 2H may be a plug 26 having a lipportion 54 and a body portion 58 configured to press against a tube wall46 so as to retain plug 26 within the delivery tube 14, and includingmarker material so as to be able to serve as a marker 24 followingejection from orifice 34 and delivery into a desired location within apatient's body. Preferably, a lip portion 54 does not extend so far asto interfere with the cutting action of sharp tip 36. A plug 26configured to serve as a marker 24 may include bioresorbable markermaterials, and be a temporary marker, or may include non-bioresorbablemarker materials, and so be a permanent marker. For example, theembodiment of a plug 26 shown in FIG. 2H is also configured to serve asa marker 24, and further includes a radiopaque element 40. Typically, aradiopaque element 40 is a permanent marker element, so that plug 26shown in FIG. 2H, for example, may be a permanent marker.

A compressible plug 26 as illustrated in FIGS. 2C and 2D may be insertedinto a delivery tube 14 through an orifice 34 as shown in FIGS. 3A and3B. FIG. 3A shows a longitudinal cross-section of a compressible plug 26disposed distal to an orifice 34 of a delivery tube 14. Compression ofbody 58 effective to reduce the size of gap 52 also reduces a lateraldimension of the plug 26 enabling a portion of the plug body 58 to beinserted through orifice 34 into tube bore 16 to be disposed in positionwithin delivery tube 14 as shown in FIG. 3B. Resiliency of plug body 58is effective to create pressure against a tube wall 46 so as to retainplug 26 in position within bore 16 in distal tube portion 18. In theembodiment shown in FIGS. 3A and 3B, gap 52 is disposed so as to facebore 16 of delivery tube 14. Alternatively, as shown in FIG. 3C, a gap52 may face away from a tube bore 16. In either embodiment, plug body 58is resiliently compressible and snugly retained within a distal tubeportion 18.

In addition, a further embodiment of a plug 26 embodying features of theinvention is illustrated in FIG. 3D. A plug 26 may contain an internalretention element 60 configured to press itself or a portion of a plugbody 58 against a wall 46 of a delivery tube 14. Such an internalretention element 60 may be radiopaque internal retention element 60,and thus, in that case, the plug 26 will also be configured to be aradiopaque marker 24. An internal retention element 60 may be anyelement, including a spring, a coil, a clip, a loop, an arch, aresilient core, or other element that is configured to help retain aplug 26 within a delivery tube 14. For example, a resilient core may bea portion of a plug body 58 which includes a resilient material andwhich provides outward force when a plug 26 is disposed within a bore 16of a delivery tube 14. A plug 26 as illustrated in FIG. 3D is a furtherexample of a compressible plug 26. It will be understood that acompressible plug 26 need not have a gap 52 in order to be resilientlycompressible effective to be inserted into and releasably retainedwithin a delivery tube 14; for example, a plug 26 may be a compressibleplug including an internal retention element 60, or where the entireplug body 58 is formed of a resilient material, such as, for example, afoam or spongy material which tends to re-expand after compression, orwhich tends to resist compression by exerting counteracting forceagainst compression.

A plug 26 may be releasably retained within a bore 16 of a delivery tube14 upon addition or insertion of an external retention element 62. FIG.4A illustrates a plug 26 embodying features of the invention disposeddistal to a distal portion 18 of a delivery tube 14. FIG. 4B illustratesthe plug 26 of FIG. 4A disposed within distal portion 18, in which plugbody 58 does not tightly contact a tube wall 46 and plug 26 is notsnugly held within delivery tube 14. Also shown in FIG. 4B is anexternal retention element 62 in the form of a conical pin. FIG. 4Cillustrates a plug 26 embodying features of the invention includingexternal retention element 62 mounted in a gap 52. Following insertionof external retention element 62 into plug 26, at least a portion ofplug body 58 contacts tube wall 46 effective to releasably retain plug26 within a distal portion 18 of delivery tube 14 effective to occludeorifice 34 and to retain a marker 24. In other embodiments, an externalretention element 62 may be a wedge, a screw, a mandrel, or any otherelement configured to tend to expand a portion of a plug body 58effective to exert force against a tube wall 46, such as by tending toexpand a plug body 58, or otherwise to aid in retaining a plug 26 withina distal portion 18 of a delivery tube 14.

A delivery tube 14 may be configured to retain and optionally to align aplug 26. For example, a delivery tube 14 may have a retaining feature64, illustrated in FIGS. 4D, 4E and 4F as a tab, configured to engage aplug 26 and to hold it in place. The retaining feature 64 shown in FIG.4D is a tab of metal formed by two longitudinal slots in the distal endof the wall 46 of delivery tube 14 that has been deflected inwardly toengage a plug 26 disposed within the bore 16, as shown in FIGS. 4E and4F (the tab shown in FIG. 4F may be formed by one radial and twolongitudinal slots). A retaining feature 64, such as a tab, may alsohelp to align a plug 26 within a delivery tube 14. A plug 26 mayoptionally also be configured to be retained by a retaining feature 64,such as a tab, as illustrated in FIGS. 4E and 4F, although a retainingfeature 64 may be effective to retain a plug 26 without any particularconfiguration of a plug 26. A plug 26 may also be configured to bealigned by a retaining feature 64, e.g., by having a notch, depression,ridge or other feature configured to engage a retaining feature 64.

Upon expulsion of a plug 26, as may be caused by distal movement of aplunger 28, a retaining feature 64 may become reconfigured to allowpassage of a marker 24 out of an orifice 34 for delivery into a patient.For example, where the retaining feature 64 is a tab intruding into atube bore 16, as shown in FIGS. 4D, 4E and 4F, the expulsion of a plug26 may be effective to bend the tab outwardly so it more closelyapproaches tube wall 46 and does not prevent movement of a marker 24through the bore 16 of a delivery tube 14. Alternatively, a retainingfeature 64 may be unaffected by movement of a plug 26 or a marker 24.For example, a retaining feature 64 may be configured to impede movementof a plug 26 or of a marker 24, without preventing such movement, and soact to releasably retain a plug 26 effective to retain a marker 24within a delivery tube 14 until the delivery of the marker 24 isdesired.

Several examples of alternative embodiments of retaining features 64 areillustrated in FIGS. 5A through 5H, representing some, but not all,suitable types and configurations of retaining features 64 embodyingfeatures of the invention. A retaining feature 64 may be disposed at anylocation on, within, or through a wall 46 of delivery tube 14, althougha distal portion 18 of a delivery tube 14 is preferred. A retainingfeature may be continuous with an orifice 34 at the distal tip 36 of adelivery tube, or may be disposed proximally of the distal tip 36 of adelivery tube 14. A delivery tube 14 may include more than one retainingfeature 64, and may include more than one shape or type of retainingfeature 64.

FIG. 5A is a plan view, and FIG. 5B is an elevation view, of a distalportion 18 of a delivery tube 14 of a marker delivery device 12embodying features of the invention, with a retaining feature 64 that isa rectangular slot 51 through tube wall 46. In FIGS. 5C and 5D, a distalportion 18 of a delivery tube 14 is shown having two retaining features64: a rectangular slot 51 and a round hole 53 through tube wall 46. Thedistal portion 18 of delivery tube 14 shown in FIGS. 5E and 5F hasretaining features 64 that are a round hole 53 and a rectangular slot 51connecting to orifice 34. The retaining features 64 illustrated in FIGS.5G and 5H are all round holes 53 spaced around delivery tube 14.Retaining features 64 may also take other shapes and may be disposed inother positions on a distal portion 18. For example, a retaining featuremay be an irregularly-shaped slot, combining in part a round hole and aslot with angled sides, and may connect with orifice 34 at tube distaltip 36.

A marker delivery assembly 10 embodying features of the invention may beused to deliver a marker 24 to a desired location within a patient'sbody. Such a desired location is typically a lesion site from which abiopsy sample has been, or is to be, taken, or a lesion has been or willbe removed. Assemblies, devices, and methods embodying features of theinvention find use, for example, in marking a breast biopsy site. By wayof illustration, the use of assemblies, devices and methods embodyingfeatures of the invention will be discussed below in terms of breastbiopsies and similar uses involving marking sites within a breast of ahuman female. It will be understood that the assemblies, devices andmethods embodying features of the invention find use in a variety oflocations and in a variety of applications, in addition to the humanbreast.

An assembly 10 or delivery device 12 can be inserted into a breast 66through a guide cannula 72, as illustrated in FIG. 6. Alternatively, anassembly 10 or delivery device 12 can be inserted directly into a breast66, using a distal tip 36 that is sharp and so is configured to pierceor puncture tissue 68, with or without an initial incision through theskin 70 of a patient. In either case, markings 44 along a delivery tube14 may be used to aid in the proper placement of the orifice 34 of adelivery tube 14, and so to aid in the proper delivery of a marker 24 toa desired location within a breast.

A plug 26 and marker 24 may be introduced into a breast 66 of a patientat a lesion site 74 adjacent or within a biopsy cavity 76, from which abiopsy sample or tissue from a lesion has been taken, as illustrated inFIG. 6. Alternatively, a plug 26 and marker 24 may be introduced into apatient's body in the absence of a biopsy cavity. This could be useful,for example, to mark a location from which to take a biopsy at a latertime. A lesion site 74 may be the site of a suspected lesion, or alesion site 74 may be the site of a known lesion. A biopsy cavity 76 maybe an existing cavity, filled, if at all, with gas or fluid, or may be avirtual cavity, substantially filled with tissue that has collapsedinto, or grown into, a site from which tissue has been previouslyremoved. A biopsy cavity 76 may adjoin, or be lined with, or be at leastin part surrounded by suspicious tissue 78, which may be remainingtissue of a lesion, newly grown tissue at least partially filling abiopsy cavity, tissue injured when the biopsy was taken, or othertissue.

Assemblies, devices and methods embodying features of the invention maybe used to deliver a marker to a desired location within a body of apatient, by inserting a delivery device 12 into a patient having markers24 retained within the bore 16 of the delivery tube 14 by a plug 26, andexpelling a marker 24 from the orifice 34 into the desired location. Amarker 24 may be expelled, for example, by depressing plunger 28 bymoving plunger handle 30. Depression of plunger 28, pushing on a marker24, is preferably effective to expel plug 26 from the orifice 34,allowing a marker 24 to exit the delivery tube 14 for delivery within apatient.

An operator may grasp a device handle 22 to guide the device 12 duringinsertion, and to steady the device 12 during depression of the plunger28. Insertion of a device 12 results in the placement of at least aportion of the device 12 adjacent a desired location. The device 12, inparticular the distal tip 36 and orifice 34 of the device 12, may beguided adjacent a desired location such as a lesion site, or a biopsycavity, or other internal body site where delivery of a marker 24 isdesired.

An initial scalpel incision in the skin is typically made in order tointroduce a device 12 into the body tissue of a patient, although inmany cases the sharp edge 34 or pointed tip 36 tip may be used to gainaccess to tissue beneath the skin without the use of an incision by asurgical tool. Insertion of the device 12 into a patient, e.g. into abreast 66 of a patient, may be guided by an operator with the aid of animaging device. A delivery tube 14, and/or markings 44, as well asmarkers 24 and optionally plug 26, may be detectable by an imagingdevice, such as an ultrasound imaging device, an X-ray imaging device, amagnetic resonance imaging device, or other imaging device.Alternatively, or additionally, insertion may be visually guided, or maybe guided by palpation or by other means.

As illustrated in FIG. 6, insertion of the device 12 into a patient,e.g. into a breast 66 of a patient, may be guided by a guide cannula aswell. Such insertion may be performed with or without the aid of animaging device, such as an ultrasound imaging device, an X-ray imagingdevice, a magnetic resonance imaging device, or other imaging device.Alternatively, or additionally, insertion may be visually guided, or maybe guided by palpation or by other means.

A plug 26 may be made with any suitable material. Typically, a plug 26is made with the same materials as a marker 24. A plug 26 may serve as amarker after its expulsion from orifice 34 and placement into apatient's body. Preferably, a plug 26 is made with a biocompatiblematerial, and provides sufficient structural strength as to retain amarker 24 within a delivery tube 14 and, where insertion of a deliverydevice embodying features of the invention is performed without the aidof a guide cannula, a material used in making a plug 26 preferably hassufficient structural strength to withstand the forces encounteredduring insertion into tissue or through skin. Materials suitable for usein making a plug 26 embodying features of the invention includepolymers, plastics, resins, waxes, glasses, ceramics, metals, metaloxides, and composites, combinations and mixtures of these materials.For example, a wax such as bone wax, or other biocompatible material issuitable for use in making a plug 26. In presently preferredembodiments, a plug 26 is made with bioresorbable polymers such aspoly-lactic acid and poly-glycolic acid. A plug may be made of more thanone material, as illustrated, for example, in FIG. 3D, showing a plug26, which may be made primarily with a plastic or a polymer, and havingan internal retention element 60, which may be, for example, a metalclip or spring.

A marker 24, including a plug 26 when configured to also serve as amarker 24, is preferably readily visible by ultrasonic imaging (USI), orby conventional imaging methods, such as x-ray and magnetic resonanceimaging methods, or by more than one imaging technique. Suitablebio-compatible materials which may be used in a marker 24 or a plug 26include polyethylene, polytetrafluoroethylene, PEBAX (made by AutochemCorp.), and the like.

Thus, biocompatible plugs 26 or markers 24 embodying features of theinvention are preferably made using materials including a bioresorbablematerial. Some particularly suitable bioresorbable materials includebio-resorbable polymers including, but not limited to, polymers oflactic acid, glycolic acid, caprolactones, and other monomers; thus, forexample, suitable bio-resorbable polymers may include poly(esters),poly(hydroxy acids), poly(lactones), poly(amides), poly(ester-amides),poly(amino acids), poly(anhydrides), poly(ortho-esters),poly(carbonates), poly(phosphazines), poly(thioesters), poly(urethanes),poly(ester urethanes), polysaccharides, polylactic acid, polyglycolicacid, polycaproic acid, polybutyric acid, polyvaleric acid, andcopolymers, polymer alloys, polymer mixtures, and combinations thereof.

A marker 24 typically should remain in place and detectable within apatient for up to at least 2 weeks to have practical clinical value.Thus, a marker 24, including a plug 26 configured to serve as a marker,is detectable at a biopsy site within a patient for a time period of atleast 2 weeks, preferably at least about 6 weeks, and may remaindetectable for a time period of up to about 20 weeks, more preferablyfor a time period of up to about 12 weeks. In some embodiments, a markermaterial for use in markers 24 and plugs 26 embodying features of theinvention is preferably not detectable about 6 months after placement ata biopsy site, and is more preferably not detectable with ultrasoundabout 12 weeks after placement at a biopsy site. Thus, a preferablein-vivo lifetime for a marker material for use in markers 24 and plugs26 having features of the invention is between about 6 weeks and about12 weeks.

In embodiments of the invention, a marker 24, and a plug 26 configuredto serve as a marker 24 following expulsion from a delivery tube 14, maybe detectable by ultrasound. Ultrasound-detectable markers 24 and plugs26 may be formed with ultrasound detectable materials, such as stainlesssteel, titanium, platinum and the like, other bio-compatible metals,ceramics, metal oxides or polymers, or composites or mixtures of thesematerials. Typically, any material which reflects ultrasound energy maybe suitable for use in an ultrasound-detectable marker. For example,materials having bubbles, internal voids, or gas-filled spaces, aredetectable by ultrasound. A marker 24 or a plug 26 may be formed so asto include voids, such as cavities, to enhance their detectability byultrasound. For example, a cavity size of between about 10 microns andabout 500 microns, preferably between about 50 microns to about 200microns, may be suitable to enhance the ultrasound-detectability of amarker 24 or plug 26.

Plugs 26 and markers 24 are configured to fit within a bore 16 of adelivery tube 14. A delivery tube 14 maybe configured to fit within aguide cannula 72, such as a guide cannula sized to accept a Mammotome®,Tru-Cut®, or SenoCor® biopsy device. Typically, a plug 26 or marker 24will have a diameter determined by the size of a bore 16, typicallybetween about 0.02″ (0.5 mm) and about 0.5″ (12 mm), preferably betweenabout 0.04″ (1 mm) and about 0.3″ (8 mm). In addition, a plug 26 ormarker 24 may have a length of between about 0.04″ (1 mm) and about 0.8″(20 mm), preferably between about 0.1″ (2.5 mm) and about 0.6″ (15 mm).

A radiopaque element 40 may be made with any suitable radiopaquematerial, including stainless steel, platinum, gold, iridium, tantalum,tungsten, silver, rhodium, nickel, bismuth, other radiopaque metals,alloys and oxides of these metals, barium salts, iodine salts, iodinatedmaterials, and combinations of these. Radiopaque materials and markersmay be permanent, or may be temporary and not detectable after a periodof time subsequent to their placement within a patient. MRI contrastagents such as gadolinium and gadolinium compounds, for example, arealso suitable for use with plugs 26 and/or markers 24 embodying featuresof the invention. Colorants, such as dyes (e.g., methylene blue andcarbon black) and pigments (e.g., barium sulfate), may also be includedin markers 24 and/or plugs 26 embodying features of the invention.

Markers 24, and plugs 26 configured to serve as markers, may alsoinclude other materials besides marker materials, including anestheticagents, hemostatic agents, pigments, dyes, materials detectable bymagnetic resonance imaging (MRI), inert materials, and other compounds.

In any of the above-described embodiments of the invention, a plug 26may include an adhesive component to aid the plug 26 to adhere to adelivery tube 14. In addition, an adhesive component may be useful toaid a marker 24 (and a plug 26 after expulsion from a delivery tube 14)to adhere to adjacent tissue within the body of a patient, such as at abiopsy site. The adhesive component may comprise a biocompatibleadhesive, such as a polyurethane, polyacrylic compound,polyhydroxymethacrylate, fibrin glue (e.g., Tisseal™), collagenadhesive, or mixtures thereof.

While particular forms of the invention have been illustrated anddescribed, it will be apparent that various modifications can be madewithout departing from the spirit and scope of the invention.Accordingly, it is not intended that the invention be limited to thespecific embodiments illustrated. It is therefore intended that thisinvention be defined by the scope of the appended claims as broadly asthe prior art will permit, and in view of the specification if need be.All patents and patent applications referred to above are herebyincorporated by reference in their entirety.

What is claimed is:
 1. An intracorporeal marker delivery device,comprising: a delivery tube which has a distal tip, a discharge orificeand an inner bore extending to the discharge orifice; at least onemarker which is slidably disposed within the inner bore; and a plugreleasably secured within the inner bore distal to the at least onemarker, the plug having a pair of diametrically opposed cantilever armsthat defines an internal gap adjacent an end portion of the plugconfigured to reduce a lateral dimension of the plug when the plug isinserted into the inner bore, wherein the end portion of the plug is aproximally diverging plug portion, and the gap extends from a proximalend of the plug into the proximally diverging plug portion, theproximally diverging plug portion being configured to resiliently engagethe delivery tube within the inner bore, and wherein the gap extendsfrom the proximal end of the plug to a terminal expanded opening withinthe plug.
 2. An intracorporeal marker delivery device, comprising: adelivery tube which has a distal tip, a discharge orifice and an innerbore extending to the discharge orifice; at least one marker which isslidably disposed within the inner bore; a plug releasably securedwithin the inner bore distal to the at least one marker, the plug havingan internal gap adjacent an end portion of the plug configured to reducea lateral dimension of the plug when the plug is inserted into the innerbore, wherein the end portion of the plug is a distally diverging plugportion, and the gap extends from a distal end of the plug into thedistally diverging plug portion, the distally diverging plug portionbeing configured to resiliently engage the delivery tube at the innerbore; and an external retention element positioned in the gap at thedistally diverging plug portion.
 3. The intracorporeal marker deliverydevice of claim 2, wherein the external retention element is a conicalpin, with a tip end of the conical pin being inserted into the gap toexpand apart the distally diverging plug portion.
 4. The intracorporealmarker delivery device of claim 2, wherein the external retentionelement is a wedge-shaped pin, with a tip end of the wedge-shaped pinbeing inserted into the gap to expand apart the distally diverging plugportion.
 5. An intracorporeal marker delivery device, comprising: adelivery tube which has a distal tip, a discharge orifice and an innerbore extending to the discharge orifice; at least one marker which isslidably disposed within the inner bore; a plug releasably securedwithin the inner bore distal to the at least one marker, the plug havinga pair of diametrically opposed cantilever arms that defines an internalgap adjacent an end portion of the plug configured to reduce a lateraldimension of the plug when the plug is inserted into the inner bore; anda radiographic marker element positioned within the plug, and withportions of the radiographic marker element being respectivelypositioned on opposing sides of the gap within the plug.
 6. Anintracorporeal marker delivery device, comprising: a delivery tube whichhas a distal tip, a discharge orifice and an inner bore extending to thedischarge orifice; at least one marker which is slidably disposed withinthe inner bore; and a plug releasably secured within the inner boredistal to the at least one marker, the plug having a pair ofdiametrically opposed cantilever arms that defines an internal gapadjacent an end portion of the plug configured to reduce a lateraldimension of the plug when the plug is inserted into the inner bore,wherein the plug includes a lip portion at a distal end of the plug, thelip portion being configured to limit the extent of insertion of theplug into the inner bore through the discharge orifice.
 7. Theintracorporeal marker delivery device of claim 6, wherein the lipportion is configured to engage an exterior circumferential surface ofthe distal tip of the delivery tube at the discharge orifice.
 8. Theintracorporeal marker delivery device of claim 6, wherein the distal tipis beveled to form a beveled distal tip, and the lip portion has abeveled proximal surface configured to engage the beveled distal tip. 9.An intracorporeal marker delivery device comprising: a delivery tubewhich has a distal tip, a discharge orifice, a side wall and an innerbore extending to the discharge orifice, the delivery tube having atleast one retention aperture extending into the side wall from the innerbore; at least one marker body which is slidably disposed within theinner bore; and a plug made of a resilient material that is positionedin the inner bore distal to the at least one marker body, the plughaving a protrusion configured to engage and extend into the at leastone retention aperture to releasably secure the plug to the side wall ofthe delivery tube.
 10. The intracorporeal marker delivery device ofclaim 9, wherein the at least one retention aperture is a plurality ofretention apertures, the plug configured to engage the plurality ofretention apertures to releasably secure the plug to the side wall ofthe delivery tube.
 11. The intracorporeal marker delivery device ofclaim 9, wherein the at least one retention aperture is in the form of aslot extending proximally from the distal tip into the side wall of thedelivery tube.
 12. The intracorporeal marker delivery device of claim 9,wherein the at least one retention aperture is a plurality of retentionapertures that includes a slot extending proximally from the distal tipinto the side wall of the delivery tube.
 13. The intracorporeal markerdelivery device of claim 9, wherein the at least one retention apertureincludes a hole extending though the side wall of the delivery tube. 14.The intracorporeal marker delivery device of claim 9, wherein the plugincludes a tab configured to engage a respective retention aperture. 15.The intracorporeal marker delivery device of claim 9, wherein the plughas a pair of spaced cantilever arms that are configured to form theinternal gap adjacent the end portion of the plug, the pair of spacedcantilever arms configured to reduce the lateral dimension of the plugwhen the plug is inserted into the inner bore of the delivery lumen andconfigured to exert a lateral pressure on the inner bore of the deliverylumen after insertion into the inner bore.